Eurotherm
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Valve Selection

How to Select a Valve

Each valve assembly consists of a valve body, an actuator and a linkage kit. The instructions and tables in this catalog will guide you in selecting the proper components or factory assemblies.

1. Determine the Application Criteria

  • Flow type required:

    • two-way, equal % or modified linear

    • three-way, mixing or diverting

  • Fluid type (hot water, steam, glycol, etc.)

  • Fluid temperature

  • Inlet pressure required

  • Existing piping or tubing size

 

Valve 2-way Flanged
2. Determine the Valve Control Form Required

The Control Form specifies the type of control action for the valve assembly. There are six different control forms. Form VB specifies the valve body only. Determine the desired Control Form for the valve assembly in your application from the table below.

3. Determine the Required Cv

For Control Form VA and VC (ON-OFF), Cv value does not affect valve body selection. Use the largest Cv available in the desired pipe size to size the valve.

 

 

For Control Form VF, VP and VS (floating and proportional control), go to the section valve sizing to determine the Cv needed for the application. To determine Cv , the following parameters must be identified:

  • inlet pressure
  • fluid temperature
  • fluid specific gravity
  • fluid flow rate in GPM (liquid) ... or
  • fluid flow rate in lbs./hr (steam)
Form Control Action Spring Actuator* Input Signal
VB None None None Valve body only
VA Two Position, ON-OFF Spring Return (NO/NC) RSE Dry contact, single input
VC Two Position, ON-OFF Non-Spring Return RSE Dry contact, dual input
VF Floating Non-Spring Return LSE Dry contact, dual input
VP Proportional, slidewire feedback Spring Return (NO/NC) RSE Dry contact, dual input
VP Proportional, slidewire feedback Non-Spring Return RSE Dry contact, dual input
VS Proportional, analog input Spring Return RSE Analog
VS Proportional, analog input Spring Return LSH Analog
VS Proportional, analog input Non-Spring Return RSE, LSE Analog

 

4. Select the Valve Body

For Control Form VA or VC (ON-OFF), use the criteria identified in (1.) above to select the desired valve body. Make sure the valve body selected has a pressure rating suitable to the fluid pressure. Specify the largest Cv rating in the desired pipe or tubing size for that selected valve body. Remember that ON-OFF control action requires an electric actuator that uses the stem-up open version of the valve body only. If the selected electric actuator is a spring return type, the valve can be configured normally open or normally closed as determined by assembly of the actuator linkage.

For Control Form VF (floating), only an electric actuator and only the stem-up open version of the valve body that meets the application criteria may be used. Make sure the valve body has a pressure rating equal to or greater than the fluid pressure. For the chosen valve body, select a valve size (PP code) for which Cv is nearest to the Cv determined from valve sizing. In some cases this choice may require the piping size to be reduced to fit the selected valve.

For Control Form VP or VS (proportional control applications) using electric actuators, you may select only the stem-up open version of the valve body that meets the application criteria (stem-up closed actuators require a hydraulic actuator). Make sure the valve body selected has a pressure rating equal to or greater than the fluid pressure. If the selected actuator is a spring return type, the valve can be configured normally open or normally closed as determined by the selection of the actuator. For the chosen valve body, select a valve size (PP code) for which Cv is nearest to the Cv determined from valve sizing. In some cases this choice may require the piping size to be reduced to fit the selected valve.

For Control Form VP or VS (proportional control applications) using electric actuators, you may select only the stem-up open version of the valve body that meets the application criteria (stem-up closed actuators require a hydraulic actuator). Make sure the valve body selected has a pressure rating equal to or greater than the fluid pressure. If the selected actuator is a spring return type, the valve can be configured normally open or normally closed as determined by the selection of the actuator. For the chosen valve body, select a valve size (PP code) for which Cv is nearest to the Cv determined from valve sizing. In some cases this choice may require the piping size to be reduced to fit the selected valve.

5. Select the Actuator

For the chosen Control Form, consult the actuator selection table on page 5–18 for an overview of the actuator types, control action, torque and travel time to assist in determining the full actuator specification. Note that there are many models of actuators available from the company in our catalog, but only those with 180° of travel and those with available linkage kits may be used for control of our valves.

Control Form VA

Electric Rotary Actuator, two position with spring return and single contact input

For an electric actuator with two-position ON-OFF control action and spring return, select the EA12 actuator. The EA12 may be configured for normally open or normally closed operation by the selection of the appropriate actuator linkage. Check the close-off pressure table on page 5–22 to determine if the EA12 actuators have enough torque to shut the valve against the expected inlet pressure criteria at the valve size selected. Check any temperature restrictions on use of this actuator as noted on the temperature tables.

Control Form VC

Electric Rotary Actuator, two position with non-spring return and single contact input

For an electric actuator with two-position ON-OFF control action and non-spring return, select the EA31 actuator. Check the close-off pressure table on page 5–22 to determine if the EA31 actuators have enough torque to shut the valve against the expected inlet pressure criteria at the valve size selected. Check any temperature restrictions on use of this actuator as noted on the temperature tables.

Control Form VF

Electric Linear Actuator, floating control with non-spring return and dual contact input
For floating control action the MF-63103 or MF-63123 actuator style must be selected. Check the close-off pressure table to determine if these actuators have enough force to shut the valve against the expected inlet pressure criteria at the valve size selected. This pressure rating must be higher than the fluid inlet pressure in the application criteria. Also check any temperature restrictions on use of this actuator as noted on the temperature tables.

Control Form VP

Electric Rotary Actuator, proportional control with slidewire feedback, spring return and dual contact input. Note that floating control action can be accomplished in Control Form VP if slidewire feedback is ignored.

For spring return proportional control action, the box style Model EA42 or EA44 low torque electric actuators may be used.

These actuators may be configured for normally open or normally closed operation by the assembly of the appropriate actuator linkage. Check the close-off pressure table to determine if the EA4x actuator has enough torque to shut the valve against the expected inlet pressure criteria at the valve size selected. This pressure rating must be higher than the fluid inlet pressure in the application criteria. Also check any temperature restrictions on use of this actuator as noted on the temperature tables.

Electric Rotary Actuator, proportional control with slidewire feedback, non-spring return, dual contact input

For proportional control action with non-spring return, the medium torque models EA52, EA54, EA56 and EA58 and high torque EA76 electric actuators with dual contact input may be used. Check the close-off pressure tables on page 5–22 to 5–24 to determine if the EA5x or EA76 actuator has enough torque to shut the valve against the expected inlet pressure criteria at the valve size selected. This pressure rating must be higher than the fluid inlet pressure in the application criteria. Also check any temperature restrictions on use of this actuator as noted on the temperature tables. Check the close-off pressure table to determine if the EA42-A or EA44-A actuators have enough torque to shut the valve against the expected inlet pressure criteria at the valve size selected.

Control Form VS

Electric Rotary Actuator, proportional control, spring return, analog input.

The new EAxx-A Series of box style actuators with integral microprocessor based electronics is available with analog input and switch selectable 180° stroke. The EA42-A and EA44-A are low

torque spring return actuators and are selected for normally open or normally closed operation.  Check any temperature restrictions on use of this actuator as noted on the temperature tables.

Electric Rotary Actuator, proportional control, nonspring return, analog input 

The new EAxx-A Series of box style actuators with integral microprocessor based electronics is also available in non-spring return versions. The EA52-A, EA54-A, EA56-A and EA58-A medium torque actuators and EA76-A high torque actuators have non-spring return action and accept analog input signals. Check the close-off pressure table to determine if the EAxx-A actuators have enough torque to shut the valve against the expected inlet pressure criteria at the valve size selected. This pressure rating must be higher than the fluid inlet pressure in the application criteria. Also check any temperature restrictions on use of this actuator as noted on the temperature tables. 

Electric Linear Actuator, floating control with nonspring return and optional analog input

The MF-63123 non-spring return linear stroke electric actuator with floating input (Control Form VF) may be converted to an analog input actuator (Control Form VS) by the addition of an optional analog input card (MFC-420 for current or MFC-8000 for voltage). Check the close-off pressure table  to determine if the MF-63123 actuator with analog input has enough torque to shut the valve against the expected inlet pressure criteria at the valve size selected. This pressure rating must be higher than the fluid inlet pressure in the application criteria. Also check any temperature restrictions on use of this actuator as noted on the temperature tables.

Options

Note that options can be specified in the actuator model code, even though they are not listed in the Actuator Selection Table. Unless noted as available factory assemblies in the Valve Assembly Tables commencing, selecting actuators with options requires that the actuator, valve body and linkage kit be purchased as separate items.

6. Select the Linkage Kit

The suitable valve/actuator combinations are listed in detail with part numbers in the Valve Assembly Tables. These tables provide the part number of the mechanical linkage kit that couples the selected actuator to the desired valve body for that application. The MF-63000 series, when used with 2" or smaller valves, requires no linkage.

7. Valve Assemblies vs. Valve Components

Once the valve body, actuator and linkage are selected, they can be ordered separately or they can be ordered fully assembled if the combination is an available factory valve assembly. Available factory assemblies are noted in the Valve Assembly Tables commencing on page 5–26. The part number will commence with the code that designates the

Control Form (VA, VC, VF, VP, VS). Only those entries in the column “Available factory assemblies” may be ordered as full assemblies. Note that the actuator received with this assembly must conform to the configuration of the actuator specified for that entry. Any other actuator configuration of options not specifically delineated cannot be ordered as a factory assembled valve.

If the selected assembly is not listed as an available factory assembly, the valve assembly must be ordered as body, actuator and linkage components and assembled locally using the complete instructions provided with the linkage kit. When ordering the valve body, actuator and linkage separately, the full model numbers for these components must be specified (see the Actuators section of this catalog).